Beneath the Volcano is the first major account of the Nage, who inhabit the central part of Flores in eastern Indonesia.
The book focuses on Nage ideas concerning a variety of spiritual beings and how these influence both ritual practices and ideas about human beings. In exploring these subjects, the author sets out to uncover a classification of spirits. While quite different from taxonomies of natural beings, Nage ways of linking named categories of spirits nevertheless reveal a regular conceptual order. In describing this order, use is made of a version of Dumont's notion of 'encompassment'. Common ideas informing relations between Nage humans and several categories of spirits are further interpreted as instances of a pervasive principle of 'symmetric inversion', according to which human beings are spirits for the spirits.